Etude enzymatique comparée de champignons entomopathogènes des genres Beauveria et Metarhizium

Résumé Les extraits antigéniques de trois champignons entomopathogènes (Beauveria bassiana, Beauveria brongniartii et Metarhizium anisopliae), soumis à l'analyse éléctrophorétique en gel d'agar révèlent au total 23 activités enzymatiques différentes (5 oxydo-réductases et 18 hydrolases), dont 18 ont été retrouvées à l'analyse immunoélectrophorétique. La carte enzymatique de ces germes complète leur analyse immunoélectrophorétique; la comparaison des isoenzymes des divers isolats permet de mettre en évidence des différences interspécifiques et intraspécifiques.Chaque souche cryptogamique se caractérise par des profils enzymatiques particuliers. Ces résultats montrent donc que l'étude des enzymogrammes est un complément utile à l'analyse immunoélectrophorétique appliquée à la caractérisation des hyphomycètes entomopathogènes. Enfin, les souches n 44 et 51 de M. anisopliae paraissent être suffisamment apparentées pour être réunies au sein d'un même biotype.     

Brachiopodes de l'Ordovicien supérieur de Libye occidentale implications stratigraphiques régionales

This paper deals with fossiliferous shales and sandstones of Ordovician age from WesternLibya. Brachiopods indicate Caradocian and Ashgillian ages at least for part of the section. On ecological grounds it is possible to demonstrate the cold water character of faunal assemblages, related to a periglacial facies. Then this series is introduced on a broader scale into the Cambro-Ordovician of Libya. Good correlations are established between Libya, Morocco and South-Africa, thus offering, through faunal control alone, a striking view of the huge size of glacial phenomena during Upper-Ordovician.     

Existence de résonances paramétriques dans des systèmes de transformation d’intérêt biologique

The study of systems exhibiting a band-pass function is completed for systems whose parameters are time-dependent. In the case of periodic parametric excitations, it is demonstrated that some systems can get into “resonance” for a particular frequency. By studying this problem, a new and probably fruitful approach of some rhythmic behaviours can be made.     

Histiocytose langerhansienne osseuse multifocale : intérêt de la scintigraphie osseuse planaire

Langerhans cell histiocytosis is a disease of the reticuloendothelial system characterized by a clonal proliferation of dendritic cells of Langerhans. This is a rare disease that primarily affects children and young adults. It can take many forms, from a single eosinophilic granuloma to widespread lesions involving multisystem life-threatening. Bone involvement is the most common, it can be uni- or multifocal. We report a case of multifocal bone Langerhans cell histiocytosis, revealed in a child aged 3 years and touched his left temporal bone and right femur. The bone scintigraphy has found a third location in right scapular. The outcome was favorable after chemotherapy. The bone lesions are characterized by lytic lesions and are responsible for pain, swelling and fractures. All the imaging techniques (radiographs, CT, and MRI) contribute to the formation of the diagnosis. Bone scintigraphy is a very sensitive examination that allows the initial staging and follow-up on treatment of skeletal manifestations.     

Observation des spermatozoïdes au fort grossissement (MSOME): intérêt et perspectives

Motile Sperm Organelle Morphology Examination (MSOME) constitutes a real improvement in ART management and outcome, as it allows detection of specific sperm anomalies on living cells, which cannot be detected by routine analysis. MSOME applied to the selection of sperm injected into the oocyte is called IMSI (Intracytoplasmic Morphologically Selected sperm Injection) and is associated with a considerable improvement of implantation, clinical pregnancy and delivery rates. A high-power microscope (X 2,000 to X 10,000) and video enhancement system are necessary and technical limitations are related to cryptozoospermia and/or severe teratozoospermia. Compared to routine sperm morphology assessment, MSOME allows the detection of subtle cephalic anomalies, such as vacuoles. These vacuoles seem to have a deleterious effect on fertilization and embryo developmentin vitro. These observations have led to a detailed classification of anomalies and this morphological diagnosis on living sperm demonstrates that most sperm selected for conventional ICSI at X 400 are actually abnormal on MSOME at X 6,000 or more. In addition to the very good results obtained in IMSI, this new approach opens up interesting prospects concerning the relationship between the phenotype of the injected sperm and its fertilization capacity and embryo development. In terms of diagnosis, MSOME could be used to select and study homogeneous groups of normal sperm or homogeneous groups of sperm exhibiting the same well defined anomaly. Such studies, associated with fine analysis of injected sperm and follow-up of each oocyte and each embryo, should provide more information about the relationship between sperm structure and function and should help to define the relevant indications for IMSI and the choice of spermatozoa to be injected.     

Comparaisons des séquences d'ADN hautement répétées chez l'homme et diverses espèces de primates

Highly repeated DNA sequences from man, five other primate species and rat were compared using five restriction endonucleases. Calculations of a similarity index based on the mobility of various bands indicate that man, chimpanzee and baboons are very similar. The sequences of the genomes studied have apparently been reorganized during primate evolution.     

Syndromes paranéoplasiques : intérêt de la tomographie par émission de positons (TEP) au 18F-fluoro-déoxyglucose (FDG)

BackgroundWe evaluated the performance of ¹⁸F-fluorodeoxyglucose (¹⁸FDG) positon emission tomography (PET) in the diagnosis of underlying malignancy in cases of suspected paraneoplastic syndrome (PS).Methods¹⁸FDG-PET was performed in 31 patients, clinically suspected to have PS. The PS were 34, among which 12 neurological diseases, eight endocrine, seven rheumatological, one dermatological and six vascular. We compared computed tomography (CT), iodine-enhanced most of the time, and ¹⁸FDG-PET reports to clinicians definitive conclusion at the end of the work-up and a follow-up period of, at least, two months.ResultsWe obtained a histological diagnosis of cancer for ten patients, but could only identify the primary site of malignancy for nine of them. ¹⁸FDG-PET showed six primary sites among which three were not seen on CT. CT disclosed four primary sites, among which one was not seen on ¹⁸FDG-PET. In one case, ¹⁸FDG-PET disclosed regional lymph node metastases whereas these were not identified by CT. Eleven non-neoplasic causes were evidenced, among which ¹⁸FDG-PET played a major role in three cases. Ten causes were still undetermined at the end of the study.ConclusionWhole-body ¹⁸FDG-PET study plays an important role in the identification of underlying malignancy in clinically suspected paraneoplastic syndromes; either by identifying the primary tumor or by directing biopsy of metastases. Furthermore, it can identify non-neoplasic causes.